MSN is powered by Inktomi.
Yahoo! bought Inktomi.
Overture bought AltaVista and Fast.
Yahoo! bought Overture.
March 2004, Yahoo! launches Yahoo! Search Technology which is a best of breed hybrid of Inktomi, AltaVista and Fast.
MSN have released into the wild, a beta of their MSNbot. This is what is currently crawling a lot of sites but IS NOT what is power the production version of MSN Search. It was powering the beta version of the MSN Search (as a tech preview) which has now been taken down.
MSN is still powered by "Inktomi", which is really a subset of Yahoo! Search Technology.
However, MSN does not take the full set of URLs in the index as provided by Yahoo! PFI results (from Inktomi Site Subit, Overture Site Match and Site Match Xchange) are not included. There is also talk that the index used by MSN is not as fresh as Yahoo! search index. I haven't seen any real proof of this.
Q) So how do you get into MSN?
A) Get crawled by Yahoo! Search Technology and wait. Use this time to build your incoming links and your content.